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Aero-engine casings commonly use composite cylindrical shell structures with excellent properties such as corrosion resistance and fatigue resistance. Still, their vibration behavior is relatively complex and may cause fatigue vibration damage, so it is essential to analyze the vibration characteristics of composite cylindrical shells. The purpose of this paper is to analyze the vibration characteristics of multilayer composite cylindrical shells subjected to external pressures and having different interlayer thickness ratios and provide some theoretical basis for the fatigue damage prediction of cylindrical shell casing to ensure the safety and stability of the engine during flight.

Firstly, the vibration differential equation with external pressure is established based on Soedel theory considering nonlinear effects, while four symmetric boundary conditions are chosen to constrain the cylindrical shell. Then the Rayleigh–Ritz method, which is more efficient and accurate in calculating large structural systems, is applied to solve the problem, and the theoretical model of three-layer cylindrical shell under external pressure is established. The accuracy of the model is verified by comparing the data with the specialized literature. Subsequently, the effects of different external pressures and different thickness-to-diameter ratios, different length-to-diameter ratios and different interlayer thickness percentages on the natural frequency of multilayer composite cylindrical shells were investigated by control variable analysis.

The conclusions obtained show that the external pressure increases the natural frequency of the cylindrical shell and that the frequency characteristics of the cylindrical shell vary for different boundary conditions. The effect of length-to-diameter ratio, thickness-to-diameter ratio and the percentage of the thickness of the intermediate layer on the natural frequency of the cylindrical shell are significantly increased under external pressure. Because the presence of external pressure increases the frequency of the cylindrical shell by about 70%, it has almost no effect on the frequency at the minimum number of circumferential waves, and the effect on the frequency at the maximum number of circumferential waves is reduced to about 50%. The frequencies in the SL-SL boundary condition are all in perfect agreement with the S-S boundary condition under the influence of different influencing factors.

In this paper, the effect of external pressure and the natural properties of the cylindrical shell under external pressure on the cylindrical shell’s frequency is considered, emphasizing the effect of different layer thickness ratios on the frequency. This paper aims to summarize the changing law between the natural frequency of the cylindrical shell itself and different design parameters during the flight pressure process. Reliable theoretical predictions are provided for analyzing the vibrational behavior of shells subjected to external pressures in aerospace, as well as a database for the practical production of cylindrical shells.

The use of additive manufacturing in many branches of industry is increasing significantly because of its many advantages, such as being able to produce complex parts that cannot be produced by classical methods, using fewer materials, easing the supply chain with on-site production, being able to produce with all kinds of materials and producing lighter parts. The binder jetting technique, one of the additive manufacturing methods researched within the scope of this work, is predicted to be the additive manufacturing method that will grow the most in the next decade, according to many economic reports. Although additive manufacturing methods have many advantages, they can be slower than classical manufacturing methods regarding production speed. For this reason, this study aims to increase the manufacturing speed in the binder jetting method.

Adaptive slicing and variable binder amount algorithm (VBAA) were used to increase manufacturing speed in binder jetting. Taguchi method was used to optimize the layer thickness and saturation ratio in VBAA. According to the Taguchi experimental design, 27 samples were produced in nine different conditions, three replicates each. The width of the samples in their raw form was measured. Afterward, the samples were sintered at 1,500 °C for 2 h. After sintering, surface roughness and density tests were performed. Therefore, the methods used have been proven to be successful. In addition, measurement possibilities with image processing were investigated to make surface roughness measurements more accessible and more economical.

As a result of the tests, the optimum printing condition was decided to be 180–250 µm for layer thickness and 50% for saturation. A separate test sample was then designed to implement adaptive slicing. This test sample was produced in three pieces: adaptive (180–250 µm), thin layer (180 µm) and thick layer (250 µm) with the determined parameters. The roughness values of the adaptive sliced sample and the thin layer sample were similar and better than the thick layer sample. A similar result was obtained using 12.31% fewer layers in the adaptive sample than in the thin layer sample.

The use of adaptive slicing in binder jetting has become more efficient. In this way, it will increase the use of adaptive slicing in binder jetting. In addition, a cheap and straightforward image processing method has been developed to calculate the surface roughness of the parts.

This case study is designed to enable students to understand the reasons behind the launch of a beauty brand grounded on traditions and culture, understand the strategies adopted by Florasis to establish its presence in the C-beauty space and emerge successful, analyze the positioning of a C-beauty brand in a highly competitive beauty market, identify the issues and challenges faced by a C-beauty brand in its efforts to disrupt the C-beauty space and suggest strategies that Florasis can adopt to emerge as a market leader in the global beauty industry.

Set in 2021, the case study discusses about the emerging C-beauty brand Florasis innovative strategies to promote the brand. Florasis was founded in 2017 with a vision to become a century old national makeup brand of China. Florasis was successful in getting on board a story-telling experience that featured traditional Chinese culture, aesthetics and heritage. It sold cosmetic products with retro packaging, concepts derived from traditional Chinese style, promoting a sense of national pride and nostalgia. The case study highlights the innovative strategies Florasis adopted like influencer marketing through key opinion leaders and key opinion customers, celebrity endorsements, user co-creation programs, social content and network marketing, brand crossovers and collaborations, etc. In April 2021, Florasis became the No. 1 cosmetic company in China with a gross merchandise value of 218m yuan and further the total sales for second quarter of 2021 reached 830m yuan, endorsing its supremacy over other global and local beauty brands in China. However, with success came along a set of challenges. Some analysts pointed that the brand was slow in innovating its product line-up, it focused more on promotions and advertisements and the brand positioning with a single sales channel, the cost performance and quality of the products and excessive marketing campaigns targeting a niche segment. Going forward, what should Florasis do to conquer the global beauty space? Can Florasis aspire to become a digitally empowered global beauty brand? Has it got the momentum? Will its direct-to-consumer model and unprecedented marketing and promotion gimmicks, help it achieve the lead in the global beauty space?

This case study is suitable for students of the graduate and undergraduate programs in management.

Teaching notes are available for educators only.

CSS 8: Marketing.

This study aims to use an additive process for the first time to develop a microfluidic device that uses centrifugal technique for precise and repeatable generation of microdroplets. Droplets have versatile applications in life sciences, but so far centrifugal devices for their production have been made mainly using standard subtractive techniques. This study focused on evaluating the applicability of 3D printing technology in the development of centrifugal microfluidic devices and investigating their properties and future applications.

First, the background of this interdisciplinary research, including the principle of droplet microfluidics and the centrifugal technique, is explained. The developed device has the form of a disc (similar to an audio CD), containing an integrated microfluidic system for droplet generation. The disc is rotated at a specific spin profile to induce controlled liquid flow and accurate production of oil-in-water microdroplets. The device was fabricated using material jetting technology. The design, operation principles, printing process parameters and post-processing steps are explained in detail.

The device was thoroughly characterised, including its mechanical properties, the impact of chemical treatment and the flow measurement of the liquids. The study confirms that the disc can be applied to produce various emulsions using centrifugal force alone. 3D printing technology enables potential mass production and other applications of the device.

The 3D printing process allowed for easy design, fabrication and duplication of the device. Compared to standard PMMA discs, a simpler fabrication protocol and a more flexible and monolithic structure were obtained. The device can be adapted to other microfluidic processes in a lab with high potential for point-of-care applications.

In view of the increasing exploration and scattered literature on digital leadership, this study aims to clarify the concept, characteristics and structure of digital leadership, identify its focus research themes and further determine future research directions in this field.

A systematic literature review is adopted in this study using 53 academic documents published in peer-reviewed journals and conference proceedings, which comprehensively combs and analyzes the research achievements.

The key characteristics of digital leadership are vision motivation, digital empowerment, innovation and entrepreneurship, cross-boundary collaboration and dynamic adaptation. Digital strategic thinking, digital insight, digital change and digital talent development are the core dimensions of digital leadership. Besides, there are three main research topics: the application of digital leadership in certain contexts including school education, government governance and business management; the development of digital leadership scale within diverse contexts; and the effectiveness of digital leadership at the organizational, team and individual levels. Digital leadership has a positive role in organizational change and innovation, team effectiveness, and employee creativity and innovation behavior.

This study helps to clarify the connotation of digital leadership and its research progress, status and gaps, which contributes to the thorough knowledge system in the digital leadership area and the promising avenues for future research.

This study aims to provide a new perspective and path to reduce the unsafe behavior of new generation of construction workers (NGCWs) in China. The purpose of this study is to explore the influencing mechanism of work-family balance on the unsafe behavior of NGCWs and test the mediating effect of job satisfaction and the moderating effect of group safety climate.

A theoretical model on the influencing mechanism of work-family balance on unsafe behavior of NGCWs was constructed through theoretical analysis. Research data were collected from 502 NGCWs via a questionnaire survey, and research hypotheses were testified with regression analysis.

The results show that work-family balance not only directly reduces NGCWs’ unsafe behavior but also indirectly reduces it through job satisfaction, which plays a partial mediating role. In addition to positively moderating the relationship between work-family balance and NGCWs’ unsafe behavior, group safety climate can also moderate the relationship between work-family balance and job satisfaction in a positive way.

This study provides practical implications for construction companies to reduce the unsafe behaviors of NGCWs from the perspective of work-family balance. Specifically, construction companies should adopt more flexible work rules, such as flexible organization and rotation systems, to increase their work autonomy. Meanwhile, construction companies need to improve the work environment and basic conditions for NGCWs, establish a reasonable salary system and provide attractive promotion opportunities to increase their job satisfaction. In addition, construction companies should provide active safety lectures and training, and supervisors should improve safety communication and interaction levels. Co-workers should remind workers about their safety attitudes and behaviors promptly. A good group safety climate will be created through the efforts of construction companies, supervisors and co-workers.

This study clarifies the influencing mechanism of work-family balance on the NGCWs’ unsafe behavior and further tests the partial mediating role of job satisfaction and the positively moderating effect of group safety climate on the influence relationship of work-family balance on job satisfaction and NGCWs’ unsafe behavior, which defines the boundary conditions of the relationship between work-family balance and NGCWs’ unsafe behavior, and promotes the effective integration of social exchange theory and theoretical system of influencing mechanism of construction workers’ unsafe behavior.

In order to explore a new estimation approach of hyperspectral estimation, this paper aims to establish a hyperspectral estimation model of soil organic matter content with the principal gradient grey information based on the grey information theory.

Firstly, the estimation factors are selected by transforming the spectral data. The eigenvalue matrix of the modelling samples is converted into grey information matrix by using the method of increasing information and taking large, and the principal gradient grey information of modelling samples is calculated by using the method of pro-information interpolation and straight-line interpolation, respectively, and the hyperspectral estimation model of soil organic matter content is established. Then, the positive and inverse grey relational degree are used to identify the principal gradient information quantity of the test samples corresponding to the known patterns, and the cubic polynomial method is used to optimize the principal gradient information quantity for improving estimation accuracy. Finally, the established model is used to estimate the soil organic matter content of Zhangqiu and Jiyang District of Jinan City, Shandong Province.

The results show that the model has the higher estimation accuracy, among the average relative error of 23 test samples is 5.7524%, and the determination coefficient is 0.9002. Compared with the commonly used methods such as multiple linear regression, support vector machine and BP neural network, the hyperspectral estimation accuracy of soil organic matter content is significantly improved. The application example shows that the estimation model proposed in this paper is feasible and effective.

The estimation model in this paper not only fully excavates and utilizes the internal grey information of known samples with “insufficient and incomplete information”, but also effectively overcomes the randomness and grey uncertainty in the spectral estimation. The research results not only enrich the grey system theory and methods, but also provide a new approach for hyperspectral estimation of soil properties such as soil organic matter content, water content and so on.

The paper succeeds in realizing both a new hyperspectral estimation model of soil organic matter content based on the principal gradient grey information and effectively dealing with the randomness and grey uncertainty in spectral estimation.

The current worldwide business landscape with large firms, asymmetric market shares and reduced competition has heralded academic and journalistic scholarship to discuss the causes and consequences of such a phenomenon. This is referred to as the emergence and sustenance of superstar firms. The previous studies make a fragmented understanding of the superstar firms, thus, there is a need to take stock of this vast and dispersed literature to set the future research agenda. The present study aims to focus on conceptual and fundamental aspects of Superstar firms’ phenomenon.

Adopting critical assessment methodology of review and systematic literature review i.e. preferred reporting items for systematic reviews and meta-analyses (PRISMA), this study investigates relevant literature. The paper critically synthesizes and analyses the definitions, measurement techniques, characteristics and roles of superstar firms.

This study defines superstar firms as more productive firms having larger market share and wider markup than other firms in industries. The study also finds that superstar firms are superior in advertisement strategies, marketing strategies, technological adoption, skilled employment and intangible investment, while the advancement of technology and the advent of globalization are the major drivers of the star firms’ phenomenon. Besides, this study uncovers the diverse roles of superstar firms concerning different economic aspects.

The review is concept centric rather than author centric. It does not incorporate quantitative data analysis for empirical investigations of hypothesis. However, the research addresses the commonalties and distinctions of factors responsible for the emergence of superstar firms, which dissects investment in public R&D, technological import subsidies and credit facilities to provide equitable opportunity and balanced development.

As the superstar firms’ phenomenon is an emerging and crucial aspect, the present study systematically analyses the phenomenon to comprehend the market structure and behavior. The study also identifies the research gaps that guide future research to understand the present setting of the market.

The ancient town of Lijiang is a representative place of ethnic minorities in China’s southwest border area jointly built by many ethnic groups. Its rich and diversified history, culture and architecture as well as its artistic and spiritual values need to be better retained and explored.

The protection and inheritance of Lijiang’s cultural heritage will be improved through the construction of digital memory resources. To guide Lijiang’s digital memory construction, this study explores strategies of digital memory construction by analyzing four case studies of well-known memory projects from China and America.

From the case studies analysis, factors of digital memory construction were identified and compared. Factors led to the discussion of strategies for constructing the digital memory of Lijiang within its design, construction and service phases.

The ancient town of Lijiang is a famous historical and cultural city in China, and it is also a representative place of ethnic minorities in the border area jointly built by many ethnic groups. The rich culture should be preserved and digitalized to offer better use for the whole nation.

This study aims to investigate the wetting behavior of AgCuTi and AgCu filler metals on selective laser melting (SLMed) Ti/TiB₂, and to analyze the microstructure and fracture characteristics of SLMed Ti/TiB₂/AgCuTi or AgCu alloy/SLMed Ti/TiB₂ brazed joints. The wetting behavior of AgCuTi and AgCu filler metals on the selective laser melted (SLMed) Ti/TiB₂ has been studied. The analysis of microstructures and fracture characteristics in vacuum-brazed SLMed Ti/TiB₂ substrate, using AgCuTi and AgCu filler metals, has been conducted to elucidate the influence of brazing temperature and alloy composition on the shear strength of the brazed joints.

Brazing SLMed-Ti/TiB₂ in a vacuum using AgCuTi and AgCu filler metals, this study aims to explore the optimal parameters for brazed joints at various brazing temperatures (800°C−950°C).

The findings suggest that elevated brazing temperatures lead to a more extensive diffusion region in the joint as a result of the partial melting of the filler metal. The joint composition changes from distinct Ti₂Cu layer/TiCu layer/filler metal to a-Ti (ss) + ß-Ti (ss)/TiCu. As the brazing temperature increases, the fracture mode shifts from brittle cleavage to ductile fracture, mainly attributed to a decrease in the CuTi within the brazed joint. This change in fracture behavior indicates an improvement in the ductility and toughness of the joint.

The originality of this study lies in the comprehensive analysis of the microstructure and shear strength of vacuum brazing SLMed Ti/TiB₂ using AgCuTi and AgCu filler metals.